1. Field of the Invention
The present invention relates to a copolymer of polyimides and polyimidines. More specifically, it relates to a novel copoly(imidine-imide) having both practical usability and heat resistance.
The copolymers of polyimides and polyimidines according to the present invention are utilized in various fields, specially as layer insulating materials for LSI, solder-resists, liquid crystal oriented films, various protective films, enamel varnishes, flexible print circuit substrates, etc., in the electric and electronic material fields; as plastic lenses, optical pick-up structures, etc., in the optical field; and as gas separation and purification apparatuses such as medical and industrial oxygen enrichment apparatuses, filter apparatuses such as food or medical water purifiers, gas-liquid separation apparatuses in the separation membrane field; and in the heat resistant adhesive field.
2. Description of the Related Art
In the prior art, polyimide resins have been used as heat resistant polymers, and for the production thereof, there has been reported, for example, the method of dehydrocyclization of polyamic acid under heat following a condensation reaction with aromatic tetracarboxylic dianhydride and a diamine in, for example, the Journal of Polymer Science, Part A, 3, 1373-1390 (1965)).
On the other hand, polyimidines are polymers developed for eliminating the defects of polyimides, and a process for the production thereof has been reported in the Journal of Polymer Science, Polymer Chemistry Edition, 14, 591-602 (1976); ibid, 14, 1485 (1976); ibid, 14, 1519 (1976); ibid, 14, 2391-2397 (1976).
The polyimide resins produced according to the afore-mentioned process have a superior heat resistance, but are insoluble or slightly soluble in general solvents, with the exception of some special solvents, which places numerous restrictions on their use.
Furthermore, polyimidine resins alleviate the defects of the afore-mentioned polyimide resins, and further, show a superior heat resistance, but it is difficult to obtain a high molecular weight and thus a practical polymer has not been obtained.
Recently, Imai et al reported high molecular weight polyimidine resins in the Journal of Polymer Science, Polymer Chemistry Edition, 21, 1241-1249 (1983), but this relates to a polyimidine using monomers synthesized through extremely complicated processed, and thus difficult to produce on a commercial scale.